Pipes, hoses and other flow lines can be used to connect a source of fluid, for example an oil tank, to a recipient, for example a furnace. The connection generally includes one or more adapter(s) that connect fittings on a flow line to those on the oil tank and the furnace. When the connection is made between the oil tank and the furnace, the fluid, oil in this example, flows freely through the flow line from the oil tank to the furnace. There are circumstances in which the flow of fluid may need to be interrupted. For example, the adapters may be sheared apart if hit, thereby causing a leak. In other examples, the flow line may rupture from the corrosive effect of the oil. The flow may also be interrupted for maintenance reasons in the absence of any failure of the connection.
Shut-off valves for closing a flow path include breakaway safety valves adapted to break when the valve is subjected to a shearing force of predetermined magnitude. Other valves include safety shut off valves which have a circumferential area of weakness therearound so that if the body is severed along the area of weakness, a stop member is removed and a poppet is allowed to close to prevent fluid flow through the body. Other devices may include a valve comprising a piston controlled shut-off valve, where the piston is spring biased to a valve-closed position and is moved against the spring bias to a valve-open position by normal operating pressure. A drop from normal operating pressure causes the piston to close the valve thereby isolating the faulty circuit. Yet other valves assembly include automatic safety valve closure systems which include a delivery pipe surrounded by a second pipe. The volume between the pipes is filled with an inert fluid, for example water. If the delivery pipe is broken or springs a leak, the change in water pressure will cause the valve to close. These and other known valves are configured to close in response to only one mode of failure of the system they occupy, although other modes of failures may be present, and are also not adapted to deliver high pressure gas.